C/C++ Source Codes

copy a file partly.(only required portion).more USEFUL for AUDIO or VEDIO files

/*filecopy.c : can copy files partly*/

#include <stdio.h>
#include <stdlib.h>

int file_copy(char *oldname, char *newname, long bytes1, long bytes2);
long get_bytes(float percent, char *source);
main()
{
char source[80], destination[80];
float percent1, percent2;

/*Get the file names*/
puts("Enter source file:");
printf("\t");
gets(source);
puts("\nEnter destination file \(WARNING: If the file exists, it will be OVERWRITTEN\): ");
printf("\t");
gets(destination);

/*Get the positions in percentage*/
puts("\nEnter start percentage (recommended: 0): ");
printf("\t");
scanf("%f", &percent1);
do
{
puts("\nEnter end percentage:");
printf("\t");
scanf("%f", &percent2);
} while ( percent2 < percent1 );

if ( file_copy( source, destination, get_bytes(percent1, source), get_bytes(percent2, source) ) == 1 )
puts("\nCopy operation SUCCESSFUL");
else
fprintf(stderr, "\nError during copy operation");

fflush(stdin);
puts("\nPress any key to exit . . . ");
getchar();
return(0);
}

/*Function for actual copying of file, return 1 on success, 0 otherwise*/
int file_copy( char *oldname, char *newname, long bytes1, long bytes2)
/*bytes1 denotes the start position in bytes, bytes2 denotes the end position*/
{
FILE *fold, *fnew;
int c;

if ( ( fold = fopen( oldname, "rb" ) ) == NULL )
return 0;

if ( ( fnew = fopen( newname, "wb" ) ) == NULL )
{
fclose ( fold );
return 0;
}

/*Set file pointer to proper start location, as specified by user*/
if ( ( fseek(fold, bytes1, SEEK_SET) != 0 ) )
{
fprintf(stderr, "\nError using fseek().");
exit(1);
}

while (1)
{
c=fgetc(fold);

/*Continue copying until end of file or until the requested limit has been reached*/
if ( !feof( fold ) && ftell(fold) <= bytes2)
fputc( c, fnew );
else
break;
}

fclose ( fnew );
fclose ( fold );

return 1;
}

/*This function finds how many bytes need to copied, calculating it from the percentage inputted by the user*/
long get_bytes(float percent, char *source)
{
long bytes;
FILE *fold;

if (percent<=100)
{
if ( ( fold = fopen( source, "rb" ) ) == NULL )
{
puts("Error opening source file");
exit(1);
}
if ( (fseek(fold, 0, SEEK_END))!=0)
{
fprintf(stderr, "\nError using fseek().");
exit(1);
}

bytes=ftell(fold);
bytes*=(percent/100);
}
else
{
fprintf(stderr, "Error in input");
exit(1);
}

fclose(fold);
return bytes;
}

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